1. Field of the Invention
The present invention is in the field of matrix band retainers for use in dental procedures. In particular, the present invention relates to matrix band retainers that are configured to clamp into the interproximal spaces between adjacent teeth to hold a matrix band in proper placement during dental filling procedures.
2. Summary of the Prior Art
In the field of dentistry, dental practitioners often treat patients who have developed cavities in a tooth. In order to treat cavities the dental practitioner removes the infected portion of the tooth and then deposits a filling material such as a composite, a resinous material, or an amalgam into the tooth preparation.
During the dental filling procedure, a matrix band is typically placed against the side of the tooth to approximately define the desired shape of the restored tooth and to keep the filling material from flowing beyond the desired tooth boundary. A matrix band typically comprises a thin metallic or plastic strip that is flexible and can be bent around the tooth being restored. The matrix band is particularly useful because it provides form for the desired shape of the resultant filling. However, if the matrix band is not properly held in place then too much or too little filling material may be deposited into the tooth preparation, thereby distorting the configuration of the restored tooth.
An improper filling can lead to dental discomfort, capture of food particles, infections, and other dental problems. To avoid these problems and to fix a distorted dental filling, it may be necessary to replace the filling. It is desirable, however, to avoid this process because it increases the time and cost of performing the filling procedure and can create anxiety and discomfort for the patient.
In order to place the matrix band into a desired placement, it is sometimes necessary to separate the teeth by placing small dental wedges in the interproximal spaces between the teeth. One inherent problem with the use of matrix bands and dental wedges, however, is that they are susceptible to moving and slipping out from between the teeth. In an attempt to avoid this problem, dental practitioners have used clamps, commonly known as matrix band retainers, to hold the matrix band and dental wedges in place during the filling procedure.
Conventional matrix band retainers consist of a rigid, cylindrical wire bent so as to have a generally circular body and one of two generally straight tines extending perpendicularly from each end of the circular body. During use, the tines are spread open and placed in the interproximal spaces between the tooth being repaired and an adjacent tooth. One problem with such matrix band retainers is that the tines do not anatomically conform to the shape of the teeth. This results in inadequate retention of the matrix band such that the matrix band in an anatomically correct conformation. In addition, some matrix band retainers can easily slip out of position.
Examples of prior art matrix band retainers include U.S. Pat. No. 6,336,810, U.S. Pat. No. 6,220,858 and U.S. Patent Publication 2002/0155410.
U.S. Pat. No. 6,336,810 shows a “flexible open ended ring with top and bottom surfaces, each forming a plane, the ring having two downward extending tines, permanently incorporated into the open ends of the ring, each tine at an obtuse angle from the bottom plane of the ring”. The bottom edge of each tine converges toward the other. Each tine is basically a rectangular planar extension from the ring.
U.S. Pat. No. 6,220,858 discloses a clamp 50. “Clamp 50 is generally semi-circular or u-shaped in plane view (FIG. 3A) and has a pair of arms 52 extending in a plane. Arms 52 are under tension and require that force be applied to move them apart. Each arm 52 has a tooth engaging surface 54 thereon. Surfaces 54 are defined by a tine 56 depending outwardly from the plane of the arms. Tine 56 is sized to extend over at least a portion of a tooth about which it is engaged. Tine 56 is bifurcated at its end to form two extensions 57. Extensions 57 defining between a notch 58A, 58B. Notch is formed to be v-shaped so that it fits over the other portion of a wedge such as that wedge shown in Figure A”.
U.S. patent application publication 2002/0155410 describes a matrix band retainer in which “the tines may be curved and/or include a wedge shaped portion to facilitate insertion of the tines into the interproximal spaces between two adjacent teeth. The “member 70 and tines 50 and 60 are formed by shaping a single piece of generally rigid wire” and “curvature of tine bodies 56 and 66 is formed by bending tines 50 and 60 during the manufacturing process”.